Electrical switch



July 10, 1 928.

' 1,676,920 L. M. PHELAN ET AL ELECTRICAL SWITCH s Sheets-Sheet 1 Original Filed Nov. 29, 1922 July 10, 1928. 1,676,920

L. A. M. PHELAN ET AL v ELECTRICAL SWITCH Original Filed NOV. 29, 1 2 5 Sheets-Sheet 2 33 M M." u, M M 7 Patented July 10, 1928.

UNITED STATES 1,676,920 PATENT OFFICE.

LOUIS A. I. PHELAN AND CLIFFORD HOTCHKISS, OF BELOIT, WISCONSIN, ASSIGNOBS,

BY DIRECT AND MESNE ASSIGNMENTS,

A CORPORATION OF INDIANA.

T0 ABSOLUTE CON-TAC-TOB CORPORATION,

ELECTRICAL SWITCH.

Application filed November 29, 1922, Serial No. 604,021. Renewed Kay 2, 1828.

Our invention relates to electrical switches designed particularly for the control ofelectrical circuits, such as may be used in connection with temperature regulating or signalling apparatus and systems.

The subject-matter of this invention includes a device making use of a liquid electrical contactor tube which consists of a container in which are mounted spaced electrodes ada ted to be bridged by a body of mercury w en the container is properly actuated or tilted from a position bordering on the horizontal.

Our invention makes use of an electrical contactor of the above type mount-ed in connection with heat responsive devices, such as thermostatic elements, The thermostatic elements are disigned to support and serve to tilt or actuate the electrical contactor into or out of circuit closing position when a predetermined temperature occurs or a change in temperature conditions obtains.

More particularly our invention refers to an electrical switch of this type in which the thermostatic element or elements are unusually efiicient, accurate and rapid in operation. 7 1

A further particular object of our invention is to provide-a read means for adjusting the above t e of evice to actuate at the required pre etermined temperatures.

A further object of our invention is to provide a switch device of the type indicated, that will be simple and economical to construct and which'will possess great durability, even when subjected to mechanical abuse and when used in connection with considerable quantities of electric current at substantial voltages.

Further objects will appear upon reference to the following description and accompanying drawings, in which- Figure 1 is a sectional view of one modification of ourinvention, the section being taken substantially on line 11 of Fig. 2 looking in the direction of the arrows;

Fi 2 is an elevational View showingthe exterior of the casing of the device shown in Fig. 1;

Fig. 3 is an elevational view. with the front portion of the casing removed;

Fig. 4 is a cross-sectional view taken substantially on the line 4-4; of Fig. 1;

Fig. 5 is an end view partly in section of another modification of our invention;

Fig. 6 is a sectional elevational view taken at right angles to the view in Fig. 5; and

Fig. 7 is a View showing a method of mounting the device of Fig. 5.

The modification of Figs. 1 through 4 comprises in a general way a tilting contactor tube 1 mounted on spiral thermostatic bi-metallic elements 2 and 3 which, in turn, are mounted on a pivoted supporting bracket 4. A casing composed of a rear portion 5 and a front or cover portion 6 serves to house the device.

The contactor tube 1 contains cooperating electrodes 7 and 8, which serve to com lete an electrical circuit when bridged by a ody of conducting liquid, such as mercury 9, at such times as the tube. is sufiiciently tilted in the proper direction.

The glass contactor tube 1 is surrounded by thin flexible metallic clamping bands 10 and 11 located at points near the ends of the tube. These bands may be formed of phospher-bronze or of similar metals. Supporting rods 12 and 13 are ivoted by screws 14 and 15 to the ends of the bands 10 and 11.. These screws 14 and 15 serve the double purpose of tightening the clamping bands 10 and 11 in place and of acting as pivotal connections for the rods 12 and 13. The use of these pivotal connections avoids excessive straining of the glass tube 1 when the thermostatic elements or other parts are subjected to unusual mechanical abuse. However, in certain instances it may be preferable to use a rigid joint at screws 14.- and 15 and in such cases these screwsmay be sufiiciently tightened or may be soldered in order to fix their position.

The rods 12 and 13 extend to points at the axis of the spirals 2 and 3 and are here soldered to stub shafts 16 and 17, respectively. If desired, an alternative form of construction may be used at this point, ,as shown in Fig. 6, in which, instead of soldering the bars to stub shafts they are threaded at 18 and extend through collars 19 and are held therein by nuts 20 and 20.

,-The elements 2 and 3 are spirally wound and maybe formed of an suitable and wellknown type of bi-metalhc ribbon composed of associated strips of copper and nickel or the like and are mounted on the pivoted bracket 4 by means of screws 21 and 22 en.- gaged by nuts 23. Insulating washers 24 and 25 serve to insulate the spirals 2 and 3 and the screws 21 and 22 from the bracket 4.

The electrical circuit to the electrodes 7 and 8 extend through lead wires 7 and 8, respectively, to the center of the elements 2 and 3 and through the spirals 2 and 3 to the screws 21 and 22. The circuit is led through the thermostatic bi-metallic elements 2 and 3 for, the particular reason hereinafter described. For certain uses, how

ever, it is desirable that the amount of cur-- rent passing throu h these elements should be less than the full amount of current traversing the contractor and for this reason shunt wires 26 and 27 are connected to the shafts 16 and 17 and the screws 21 and 22 and hence are electrically in parallel with the spirals 2 and 3. The leads 26 and 27 are retained at screws 21 and 22 beneath washers 28 and 29.

The bracket 4 is pivoted to the casing member 5 at 30 by means of a screw 31 or like means. The bracket is further pivoted to a support 32 by means of a rivet 33 or the like. The bracket 32 is attached to the casing member 5 by screws 34.

Flexible leads 35 and 36 extend from the screws 21 and 22 to conductors 37 and 38 which lead to the external circuit in which the device is connected.

The casing member 5 is provided with an extension recess 40, through which the conductors 37 and 38 extend and are sealed in place by sealing wax 41. The conductors 37 and 38 pass to the exterior of the casing through holes 42, having insulated protecting bushings 43.

The two parts 5 and 6 of the casing are terior of the casing. The adjusting lever 50 issecurely attached to the bracket 4 by screws 51 and serves as a convenient'means for adjustin this bracket about its pivoting axis an 7 from a point exterior to the casing. The flange 45 may be provided with a calibrating scale at 52, if desired.

The operation and one method ofusing' the device will now be outlined. The particular modification shown in Figs. 1 through 4 is designedto be mounted the wall of a room or compartment, the temperature of which is to be regulated. The

flange 45 may be mounted flush with the wall surface. The conductors 37 and 38 are connected directly in series with a motoroperated heating or cooling equipment, of any of the usual and suitable types, or with any other desired form of load.

Assuming that the room temperature 15 at or near the desired point, the lever 50 is turned so that the contactor tube 1 is in a substantially neutral position ready to either close or 0 en the circuit with a very slight change 0 temperature. If it is assumed that the device is-being used for the regulation of a heating equipment and that the room is at the desired temperature, then the heating apparatus should not be in full operation and consequently, the contactor tube 1 should be in open circuit position with the body of mercury 9 out of contact with the electrodes 7 and 8. However, as the room temperature drops a predetermined amount, the spiral bi-metallic elements 2 and 3 will become modified in shape due to the temperature change and will tilt the con- ,tactor tube 1 about its axis into circuitclosing position.

The current to the contactor tube 1 which will start the operation of the heating equipment and will now flow partly through the spiral elements 2 and 3 and partly through the'shunts 26 and 27. The spiral elements 2 and 3 will now begin to return to their former position and shape and will begin to tilt the contactor tube 1, as a result of two causes. First, the heating equipment will begin to restore the former temperature in the room, and second, the current through these elements will slightly heat them, thus aiding in bringing them to normal temperature.

This current heating eifect in the elements 2 and 3 has a particular advantage in this type of heat regulating switch, which will now be outlined. As the contactor tube 1 turns to its closed circuit position, the moving body of conducting liquid 9 very materially alters the center of gravity of the tube. It is desirable that this alteration of the center of gravity should occur in order to insure a very positive and abrupt make and break of the electric circuit in the contactor. Yet it will be obvious that with such astructure that an appreciable temperature change will "be required to restore the contactor to Its normal position, since sufiicient energy and motion are necessary to move the body of conducting liquid 9 back to its former position. Hence, in order to use this type of regulating switch where the temperature must be regulated very accurately, it is advantageous to supplement the action of the increased .room temperature upon the spiral elements with the heating action of the current or part of the current passing through the elements 2 and 3.

temperature change for operating the con-- tactor tubes may be conveniently reduced to approximately two degrees. The sensitiveness of the device in this respect maybe adjusted by properly proportioning the shunt wires 26 and 27 or by properl designing the conducting cross-section of the spiral elements 2 and 3. Hence it is obvious that myinvention renders it possible to use a contactor tube which is very reliable in operation and still regulatesthetemperature with great accuracy.

In Figs. 5, 6 and 7 a modification is shown which is especially adapted to be mounted in a refrigerating chamber orxice-box. The housing of this modification comprises a body portion 53 connected by'sorews 54 to a cover portion 55. At the lower side of the body portion 53, a connection box 56 is shown into which electrical conduits 57 and 58 may be fastened and in which circuit connections may be made .by the usual methods.

The upper side of the cover portion 55 is provided with a threaded bushing 59 engagmg a suitable length of pipe or rod 60 terminating at its upper end by a pipe flange 61, adjusted to rest firmly against a ceiling 62 of an ice-box compartment by screwing the pipe 60 in or out of the bushing 59.

This structure serves as a convenient means for frictionall and removably securmg the switching devlce between a floor 63 and the ceiling 62 of an ice-box compartment. The

necessity of puncturing these floor and ceiling surfaces by screws or. nails is thus avoided.

In the modifications shownin Figs. 5, 6 and 7 thermostatic elements 64 and 65 are wound in the form of facin conical spirals as shown. The particular a vantages of this form of conical or helical spiral are that a greater amount of space is provided for the mountings and for the'conneoting leads of the contactor tube and that larger ortions of the surface areas of the spiral rib us are directly exposed to the atmosphere. These large exposed surface areas insure a more rapid actuation of the thermostatic elements which is a very important consideration in accurate temperature regulation.

An adfjusting lever 66 extends to the exterior o the and is operated in a manner similar to the lever 50. In this modificationthe leads may be connected through the-spiral elements as described above'and as U.- S. Patents Nos. 1,598,874 and 1,598,875.

shown at 67 but, if the device is used solely with refrigeration apparatus, the leads are preferably independent of the spiral elements as indicated at 68 by dotted lines.

The terms contactor tube and liquid contactor as employed herein refer to a well known type of mercury electric switch which comprises an hermetically sealed container in which spaced electrodes are disposed, and a movable body of conducting liquid, such as mercury, the latter serving to make and break the electric circuit between the said electrodes. Such mercury electric switches are shown and described 1n While we have shown and described several embodiments of our invention, it is to be understood that many modifications may be made therein without departing from the spirit and scope of the appended claims, and we desire that only such limitations shall be imposed upon our invention as are specifically pointed out in the claims and such as are required by the prior art.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent in the United States is:

1. The combination with an actuator, of a liquid contactor tube, and means for mounting'said tube in a manner to be rotatable about its transverse axis by said actuator, said means comprising clamps atspaced points on said tube and rods extending from said clamps to points on said axls and then along said axis.

2. The combination with an actuator, of a liquid contactor tube, and means for mounting said tube in a manner to be r0.- tatable about its transverse axis by. said actuator, said means comprising clamps at. 'spacedpoints on said tube and rods flexibly'connected to said clamps and extending to and fixed to supporting structure at points on said axis.

3. The combination with an actuator, of a liquid contactor tube, and means for mounting said tube in a manner to be rotatable about its transverse axis by said actuator, said means comprising clamps consisting of flexible metallic bands surrounding said tube at spaced points and rods extending from said clamps to points on said axis and then along said axis.-

4. The combination with an actuator, of a liquid contactor tube, and means for mounting said tube in a manner to be rotatable about its transverse axis by said actuator, said means comprising clamps at spaced points on said tube and rods connected to said clamps and extending to points on said axis and then along said axis, the connection ing said tube in a manner to be rotatable about it's transverse axis by said actuator, said means comprising two clamps at spaced points on said tube and rods at opposite sides of said tube extending from said clamps to points on saidaxis and then along said axis in each direction respectively from said tube.

6. The combination of a liquid contactor tube, two coaxial spiral thermostatic elements, and means for supporting said tube between said elements in a manner to be rotatable about its transverse axis comprising clamps at spaced points on said tube, rods fixed to said clamps and extending on each side of said tube to points in said axis and along said axis and fixed to the inner ends of said spiral elements.

7. A thermostatic switch comprising two thermostatic elements formed of conducting material and having -corresponding ends thereof fixed, a tiltable liquid contactor comprising electrodes co-operating with each other to make and breaka circuit, said contactor being mounted on and wholly M supported by the free ends of said elements, an electrical circuit to said contactor connected through said'elements to said electrodes, and bridging connections electrically in parallel with said-elements.

8. An electrical device comprising two spaced thermostatic coils, a liquid contactor operable upon being tilted and wholly supported upon the free ends of said coils, supporting means for securing thereto the other ends of said coils, said supporting means being pivotally mounted in order to provide for adjustment of the actuating position of said contactor, said coils being electric-ally insulated from each other, and electrical connections for said contactor comprising said coils.

In Witness whereof, we have hereunto subscribed our names.

LOUIS A. M. PHELAN. CLIFFORD HOTCHKISS. 

